In the Woods

The murder of twelve-year-old Katy Devlin is ultimately solved when Rob Ryan realizes the weapon used to violate her body postmortem was a trowel, which leads detectives back to the archaeological dig's finds shed as the actual murder site. Only Dr. Hunt, site supervisor Mark Hanly, and student Damien Donnelly had keys. Under interrogation, Damien breaks down and confesses to killing Katy, though he initially refuses to explain why. Cassie Maddox and Sam O'Neill eventually get the full truth: Damien had fallen in love with Rosalind, Katy's older sister, who manipulated him into believing their father was abusing the girls and that Katy was orchestrating it, convincing Damien he needed to kill her to protect Rosalind. Maddox, recognizing Rosalind as a psychopath, wears a wire and tricks her into confessing that she had been slowly poisoning Katy for years out of jealousy over her ballet talent, and had engineered Damien into committing the murder while she kept an alibi. Because Rosalind is only seventeen, her recorded confession is inadmissible. Damien is convicted and sentenced to life in prison; at trial, Rosalind falsely testifies that he killed Katy out of romantic revenge. Their father, Jonathan Devlin, admits to Ryan that he long suspected Rosalind but didn't want to face it; he plans to keep her under close watch and get her psychiatric help, while sending the traumatized younger twin, Jessica, who had attempted suicide, to live with relatives for her own safety.

The 1984 disappearance of Ryan's childhood friends Jamie and Peter is never solved. Ryan does recover fragments of memory by camping alone in the woods: he remembers kissing Jamie, Peter's plan for the three of them to run away together, and being interrupted by an unseen, menacing presence before the other two children vanished over a stone wall while Ryan fell behind. He blacks out again before learning anything more, and afterward flees in a panic, effectively losing that memory for good. Jonathan Devlin, who as a teenager had been involved in a woodland assault Ryan witnessed as a child, denies any connection to the disappearances. The case of Jamie and Peter remains permanently unresolved.

Ryan's personal life collapses over the course of the investigation. After finally sleeping with Cassie Maddox, his closest friend and partner, he panics at the prospect of intimacy and pushes her away, and their friendship deteriorates. His obsessive, borderline inappropriate fixation on Rosalind almost leads him to kiss her before she storms off angry at his hesitation. When Superintendent O'Kelly learns Ryan concealed his own connection to the 1984 case, he is furious; Ryan initially blames Maddox for exposing him, but she shows him video proof it was Rosalind who revealed his identity during interrogation. Ryan is suspended and investigated, keeps his detective rank only to avoid a scandal, but is effectively finished as a real detective, demoted to floater duties assisting other cases.

In the aftermath, Maddox transfers out of the murder squad into Domestic Violence and becomes engaged to Sam O'Neill. Late one night Ryan drunkenly calls her to apologize and say he loves her, but she says nothing and hangs up. Meanwhile, O'Neill's investigation into who threatened Katy's father over his motorway protest campaign uncovered corruption involving O'Neill's own politician uncle, and O'Kelly ordered him to bury the evidence, which he does; the motorway project proceeds as planned, destroying the archaeological site. In the closing scene, Ryan goes to watch the motorway construction, and a worker hands him an ancient antlered pendant unearthed near the ceremonial stone table, offering to let him keep it. Ryan hands it back and walks away, leaving both the Devlin case's lingering mysteries and his own childhood trauma unresolved.